Former CIA director George Tenet told Charles Gibson he feels "great regret" when he looks back at the photos of Colin Powell at the United Nations, which were taken as the former secretary of state made the case for an Iraq invasion in 2003 and claimed Iraq had weapons of mass destruction.

"The secretary of state of the United States is in front of the world, and ultimately, you know, his credibility's undermined because the data that he based his speech on, doesn't hang together. It's a low moment," Tenet said. "We pride ourselves our whole lives on being accurate and being right … You don't look back on it fondly."

Tenet left his post with the CIA in 2004 before the presidential election. He writes about his years there in the book "At the Center of the Storm: My Years at the CIA," which is drawing criticism by some in the Bush administration.

Powell's Feb. 6, 2003, U.N. speech, which led to the Iraq invasion, was based on what turned out to be false information from a fraudulent source regarding the existence of WMDs in Saddam Hussein's arsenal. Tenet refutes accusations that he knew the data was false.

"That's just repugnant to me, I would never let the secretary of state … someone who I was very close to, who represented the United States of America, in front of the eyes of the world, go out there and make a false statement. Never," Tenet said.

But in an interview with ABC News earlier this year, Powell's former Chief of Staff Col. Lawrence Wilkerson stated that the former secretary of state was intentionally misled about WMDS in Iraq.

Tenet said it's not true: "It's really serious for someone to say the director and the deputy director, essentially, cooked the books to go make the case for war and didn't tell the secretary of state. There's no way on this God's green Earth that that would ever happen, none."

Thrown a 'Curveball' on Iraq

Tenet said he trusted the CIA source at the time, but would later learn the German intelligence community had tried to warn him about Curveball's credibility.

"The chief of the German service sent us a letter, which I never got, and we didn't find out the existence of, until 2006 … he could not independently verify what, what Curveball was telling us, but that letter was never brought forward," Tenet explained.

On the issue of the possible connection between al Qaeda and Iraq, Tenet told Gibson he did not support that view and expressed that to Bush, who was given different guidance from Vice President Dick Cheney.

"We wrote what we believed, we stayed true to it. If people want to believe what other views are around town … if they want to divert from the intelligence, they're playing without a safety net from the perspective of the record," Tenet said.

He also writes about the handling of high-level terror suspects, and told "60 Minutes" on Sunday that the CIA does not torture. In his book he refers to "enhanced interrogation techniques."

"It's something important for everybody to understand about this. Whatever you call them, it was authorized. It was legal, according to the attorney general of the United States," Tenet said. "Nobody held us back. This is not a secret from the, from the perspective of the CIA going off and doing something."

Gibson asked Tenet if he considers the practice of water-boarding, in which interrogators blindfold a prisoner and simulate drowning, to be torture.

"I'm not gonna talk about techniques. I'm just not gonna go there with you," Tenet replied.

He also wanted to point out the context of fear he was working in after the Sept. 11 attacks.

"The plotlines that we were dealing with -- that dealt with nuclear weapons in New York City, apartment buildings blowing up, plots against airliners, plot against the airport -- no one will remember … how much we did not know about what was going on inside the United States. And so, there's a context to all this," Tenet said.

He added that intelligence officers think about values and the protection of the American people "very seriously."

"And what we need from the political leadership is continuity of purpose, bipartisan leadership, everybody being on the same page because here's where we don't want to be as a country. The next time a terrorist attack occurs, don't race and swing the pendulum one way or the other, just let's make a determination, and figure out where we want to be," he said.

Tenet's now speaking out nearly three years after his resignation from the CIA -- making criticisms he did not make during the 2004 election.

"I thought I had some responsibility to think about what had just happened, reflect on what I saw, get my thoughts together, think about this in a serious way, not dump this in the middle of some election," Tenet said. "I was too close to what had just happened … you don't want to write in anger, you want to write in balance, you want to give people some historical perspective. I'm now a teacher … you know, what would you tell your students you learned about this time period?"